How do I create docs for an API that changes often?

For an API that changes often, the best docs are the ones that are easy to update, automatically generated where possible, and tightly tied to the source of truth.

Good approach

1. Make the API spec the source of truth

Use a machine-readable spec like:

• OpenAPI / Swagger for REST APIs
• GraphQL schema for GraphQL APIs
• AsyncAPI for event-driven APIs

This lets you generate docs, SDKs, examples, and validators from the same definition.

2. Automate documentation generation

Avoid hand-written docs for endpoints, schemas, and parameters if they change frequently.

Automate:

• endpoint reference docs
• request/response examples
• schema definitions
• auth requirements
• error codes

Tools:

• Swagger UI / Redoc for OpenAPI
• Stoplight
• Postman documentation
• Docusaurus or MkDocs with generated API sections

3. Keep narrative docs separate from reference docs

Split docs into:

• Reference docs: generated from spec, highly accurate, detailed
• Guides/tutorials: human-written, stable, explain workflows and use cases

This reduces maintenance because only the reference part changes often.

4. Version your API and docs

If the API changes often, assume breaking changes will happen.

Use:

• /v1, /v2 in routes or headers
• separate docs per version
• changelogs and migration guides

Include:

• what changed
• whether it’s breaking
• how to migrate

5. Put docs in the same repo as the API

This makes it easier to update docs in the same pull request as code changes.

Best practice:

• changes to endpoints require docs updates in the same PR
• CI checks fail if spec/docs are out of sync

6. Add examples and tests

Docs stay useful when they’re validated.

Use:

• example requests/responses from real tests
• contract tests to ensure docs match behavior
• automated linting for specs

7. Document change frequency clearly

For fast-moving APIs, tell users:

• what is stable
• what is beta/experimental
• deprecation policy
• support window for old versions

Practical setup example

A common workflow:

1. Define API in OpenAPI
2. Generate docs with Redoc or Swagger UI
3. Store spec in the API repo
4. Add CI checks for:
   • spec linting
   • breaking change detection
   • example validation
5. Publish versioned docs automatically on release

What to avoid

• Long manually maintained endpoint pages
• Docs in a separate repo with no automation
• Unversioned APIs with no changelog
• Examples that aren’t tested

Recommended structure

A strong docs site usually has:

• Overview
• Quickstart
• Authentication
• Core concepts
• API reference auto-generated
• Examples / tutorials
• Errors
• Changelog
• Deprecation policy

If you want, I can also suggest a specific docs stack for your API type, like REST, GraphQL, or internal microservices.